For stapling sheets in a labor-saving manner, the office machine is usually equipped with a sheet processing device for facilitating automatically stapling sheets. Generally, the sheet processing device is located in the vicinity of the sheet discharge tray of the office machine. When plural sheets have been printed or scanned and ejected to the sheet discharge tray, the edges of these sheets are aligned with each other by the sheet processing device. After the office machine has performed the printing or scanning tasks, the aligned sheets are transferred to a stapler. By the stapler, these sheets are jointed together. In such way, the labor cost is reduced, and the working efficiency is enhanced.
FIG. 1 is a schematic view illustrating a conventional sheet processing device. As shown in FIG. 1, the conventional sheet processing device 10 comprises a supporting plate 11, a paperweight 12, an edge alignment element 13, and a stapler guide 14. The supporting plate 11 is used for supporting plural papers 15. The stapler guide 14 is located at a side of the supporting plate 11. In addition, the stapler guide 14 has a slant surface 141 and an entrance 142.
After the plural sheets 15 are introduced into the supporting plate 11, the paperweight 12 is firstly moved downwardly in a direction A to flatten plural sheets 15, and then the paperweight 12 is moved upwardly in a direction B to be returned to the original position. After the flattening action of the paperweight 12 is completed, the edge alignment element 13 is moved in a direction C to push the plural sheets 15. Consequently, the edges of the plural sheets 15 are aligned with each other, and the curled portions 151 of the plural sheets 15 are gradually moved toward the stapler guide 14 to be contacted with the slant surface 141 of the stapler guide 14. As shown in FIG. 1, because of the slant surface 141, the entrance 142 has an externally-wide and internally-narrow profile. When the plural sheets 15 are introduced into the entrance 142 of the stapler guide 14, the curled portions 151 are suppressed by the slant surfaces 141, so that the curled portions 151 are further flattened. In such way, the plural sheets 15 can be smoothly introduced into the stapler guide 14 and stapled by the stapler guide 14. By the conventional sheet processing device 10, the possibility of upturning the curled portions 151 of the plural sheets 15 will be minimized, and thus the plural sheets 15 can be easily stapled.
However, since the curled portions 151 of the plural sheets 15 are suppressed by the slant surface 141 of the stapler guide 14 of the conventional sheet processing device 10 in order to smoothly stapled, some drawbacks may occur. For example, when the plural sheets 15 are moved toward the stapler guide 14 in the direction C, the curled portions 151 of the plural sheets 15 are possibly bent by the slant surface 141. Under this circumstance, the corners of the plural sheets 15 are possibly folded. That is, even if the plural sheets 15 can be smoothly stapled, the plural sheets 15 are suffered from unrecoverable damage.